Aerodynamic drag reducing apparatus

Abstract

A drag reducing apparatus is provided for use with vehicles having surfaces that are not streamlined. The apparatus includes an exterior cover that forms a drag reducing shape when the apparatus is fully extended. The apparatus can be retracted to a space saving configuration. A scissors linkage extends and retracts the apparatus. The scissors linkage can be motorized, and the motor can extend the scissors linkage by turning in a first direction and can retract the apparatus by turning in a second direction. The scissors linkage can hold the exterior cover taut when the apparatus is fully extended. The scissors linkage can support the exterior cover at intermediate locations when the apparatus is not fully extended. The apparatus can include support linkages and intermediate moveable members that support the exterior cover and define the drag reducing shape.

What is claimed is: 
     
       1. A drag reducing apparatus comprising:
 a scissors linkage; and 
 a flexible tension member routed through the scissors linkage; 
 wherein when the tension member is driven in a first direction the scissors linkage extends thereby extending the drag reducing apparatus; 
 wherein when the tension member is driven in a second direction the scissors linkage retracts thereby retracting the drag reducing apparatus. 
 
     
     
       2. The drag reducing apparatus of  claim 1 , wherein the flexible tension member is driven by a pulley. 
     
     
       3. The drag reducing apparatus of  claim 1 , wherein the flexible tension member does not support compressive loads. 
     
     
       4. The drag reducing apparatus of  claim 1 , wherein a center of gravity of the scissors linkage is at an elevation, wherein the elevation of the center of gravity of the scissors linkage is at a high elevation when the scissors linkage is at a location between an extended configuration and a retracted configuration, and wherein the elevation of the center of gravity of the scissors linkage is lower than the high elevation when the scissors linkage is at both the extended configuration and the retracted configuration. 
     
     
       5. The drag reducing apparatus of  claim 1 , further comprising an aerodynamic surface that is deployed by the scissors linkage when the scissors linkage extends the drag reducing apparatus and is retracted by the scissors linkage when the scissors linkage retracts the drag reducing apparatus. 
     
     
       6. The drag reducing apparatus of  claim 5 , wherein the aerodynamic surface is a flexible aerodynamic surface. 
     
     
       7. The drag reducing apparatus of  claim 1 , wherein the drag reducing apparatus is adapted to mount behind a vehicle. 
     
     
       8. A drag reducing apparatus comprising:
 a mounting structure adapted to mount the drag reducing apparatus to a vehicle; 
 an extendible and retractable compression arrangement; 
 an extendible and retractable tension arrangement including at least one flexible tension member; 
 a first connection between the extendible and retractable compression arrangement and the extendible and retractable tension arrangement; 
 a second connection between the extendible and retractable compression arrangement and the mounting structure; and 
 a third connection between the extendible and retractable tension arrangement and the mounting structure; 
 wherein the first, the second, and the third connections are arranged in a triangle at least when the extendible and retractable compression arrangement and the extendible and retractable tension arrangement are extended; and 
 wherein the drag reducing apparatus is supported by compression in the extendible and retractable compression arrangement and by tension in the extendible and retractable tension arrangement at least when the extendible and retractable compression arrangement and the extendible and retractable tension arrangement are partially extended. 
 
     
     
       9. The drag reducing apparatus of  claim 8 , wherein the at least one flexible tension member is routed through the extendible and retractable compression arrangement and wherein tension in the at least one flexible tension member urges the extendible and retractable compression arrangement to extend. 
     
     
       10. The drag reducing apparatus of  claim 9 , wherein the extendible and retractable compression arrangement includes a scissors linkage. 
     
     
       11. The drag reducing apparatus of  claim 8 , wherein the extendible and retractable compression arrangement includes a scissors linkage. 
     
     
       12. The drag reducing apparatus of  claim 8 , wherein the first connection is at an end of the drag reducing apparatus at least when the extendible and retractable compression arrangement and the extendible and retractable tension arrangement are extended. 
     
     
       13. The drag reducing apparatus of  claim 8 , wherein the first connection is between an end of the drag reducing apparatus and the mounting structure at least when the extendible and retractable compression arrangement and the extendible and retractable tension arrangement are extended. 
     
     
       14. The drag reducing apparatus of  claim 8 , wherein the extendible and retractable compression arrangement extends beyond the first connection away from the mounting structure at least when the extendible and retractable compression arrangement and the extendible and retractable tension arrangement are extended. 
     
     
       15. The drag reducing apparatus of  claim 8 , further comprising an exterior cover, wherein the exterior cover is tensioned by the extendible and retractable compression arrangement at least when the extendible and retractable compression arrangement is fully extended. 
     
     
       16. A drag reducing apparatus comprising:
 a drag reducing exterior adapted to reduce drag on a vehicle when the drag reducing apparatus is in an extended configuration and is positioned behind a rear end of a vehicle; and 
 a linkage arrangement adapted to configure the drag reducing exterior of the drag reducing apparatus in the extended configuration and also adapted to configure the drag reducing exterior of the drag reducing apparatus in a retracted configuration, the linkage arrangement positioned below a cargo hold of the vehicle when the drag reducing apparatus is in the retracted configuration. 
 
     
     
       17. The drag reducing apparatus of  claim 16 , wherein at least a portion of the linkage arrangement is positioned underneath the cargo hold of the vehicle when the drag reducing apparatus is in the retracted configuration and configured to allow access to at least one rear door of the cargo hold of the vehicle. 
     
     
       18. The drag reducing apparatus of  claim 16 , wherein at least a portion of the linkage arrangement is positioned underneath the cargo hold of the vehicle and at a side of the vehicle when the drag reducing apparatus is in the retracted configuration and configured to allow access to at least one rear door of the cargo hold of the vehicle. 
     
     
       19. The drag reducing apparatus of  claim 16 , wherein the linkage arrangement includes a scissors linkage. 
     
     
       20. The drag reducing apparatus of  claim 16 , further comprising a flexible tension member, wherein tension in the flexible tension member at least partially supports the drag reducing apparatus at least when the drag reducing apparatus is in the extended configuration.